Donald Trump has slapped down a bid by the EU to shield European businesses from the impact of new US sanctions against Iran.

The US president tweeted that new measures taken against the Middle Eastern country have "officially been cast".

He added: "Anyone doing business with Iran will NOT be doing business with the United States. I am asking for WORLD PEACE, nothing less!"

It comes hours after British Foreign Office minister Alistair Burt sought to calm UK businesses by assuring them a "blocking statute" passed by the EU would protect them from the sanctions.

The Iran sanctions have officially been cast. These are the most biting sanctions ever imposed, and in November they ratchet up to yet another level. Anyone doing business with Iran will NOT be doing business with the United States. I am asking for WORLD PEACE, nothing less!

He told BBC radio: "If a company fears legal action taken against it and enforcement action taken against it by an entity in response to American sanctions then that company can be protected as far as EU legislation is concerned.

"It is a commercial decision for companies whether they continue to work in Iran."

Measures hitting key metals, such as gold, and the automotive industry came back into force on Tuesday.

German automaker Daimler announced soon after it was halting its business activities in Iran.